1 /* ===-- fixxfti.c - Implement __fixxfti -----------------------------------=== 2 * 3 * The LLVM Compiler Infrastructure 4 * 5 * This file is dual licensed under the MIT and the University of Illinois Open 6 * Source Licenses. See LICENSE.TXT for details. 7 * 8 * ===----------------------------------------------------------------------=== 9 * 10 * This file implements __fixxfti for the compiler_rt library. 11 * 12 * ===----------------------------------------------------------------------=== 13 */ 14 15 #include "int_lib.h" 16 17 #ifdef CRT_HAS_128BIT 18 19 /* Returns: convert a to a signed long long, rounding toward zero. */ 20 21 /* Assumption: long double is an intel 80 bit floating point type padded with 6 bytes 22 * ti_int is a 128 bit integral type 23 * value in long double is representable in ti_int 24 */ 25 26 /* gggg gggg gggg gggg gggg gggg gggg gggg | gggg gggg gggg gggg seee eeee eeee eeee | 27 * 1mmm mmmm mmmm mmmm mmmm mmmm mmmm mmmm | mmmm mmmm mmmm mmmm mmmm mmmm mmmm mmmm 28 */ 29 30 COMPILER_RT_ABI ti_int 31 __fixxfti(long double a) 32 { 33 const ti_int ti_max = (ti_int)((~(tu_int)0) / 2); 34 const ti_int ti_min = -ti_max - 1; 35 long_double_bits fb; 36 fb.f = a; 37 int e = (fb.u.high.s.low & 0x00007FFF) - 16383; 38 if (e < 0) 39 return 0; 40 ti_int s = -(si_int)((fb.u.high.s.low & 0x00008000) >> 15); 41 ti_int r = fb.u.low.all; 42 if ((unsigned)e >= sizeof(ti_int) * CHAR_BIT) 43 return a > 0 ? ti_max : ti_min; 44 if (e > 63) 45 r <<= (e - 63); 46 else 47 r >>= (63 - e); 48 return (r ^ s) - s; 49 } 50 51 #endif /* CRT_HAS_128BIT */ 52
